grizzly: snapshots for LVM-backed root disks

[Tom Fifield]

https://review.openstack.org/21591 added a new feature/config option - snapshots for LVM-backed root disks

    Uses the built-in LVM snapshotting mechanism to create a new
    snapshot, use qemu-img to extract the full root into an image file,
    then delete the snapshot volume. Although we typically zero deleted
    LVM volumes manually, this is not necessary for snapshots, as LVM
    handles it for us (per the documentation).

   46 cfg.IntOpt('libvirt_lvm_snapshot_size',
   47 default='1000',
   48 help='The amount of storage (in megabytes) to allocate for LVM'
   49 ' snapshot copy-on-write blocks.'),

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/22168

[Tom Fifield (fifieldt)]

https://review.openstack.org/22168

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/22168
Committed: http://github.com/openstack/openstack-manuals/commit/f624f5ed0f4c66d9935bcd0bee5dee5b952fc6a5
Submitter: Jenkins
Branch: master

commit f624f5ed0f4c66d9935bcd0bee5dee5b952fc6a5
Author: Tom Fifield <email address hidden>
Date: Mon Feb 18 16:04:01 2013 +1100

    Add libvirt_lvm_snapshot_size option

    fixes bug 1128581

    Prior to Grizzly, snapshots did not work if you were running LVM as
    your backing root disk.

    It turns out, the documentation never had anything mentioning it
    didn't work. So this change is as simple as adding a configuration
    variable.

    Change-Id: I02de367eff06477727d1fee1a82c34928a76d384